On a conference call, Activision Blizzard CEO was pretty open about his thought process. Unless he can beat a horse into tatters, he doesn't want to ride it. MTV Multiplayer has the story:

Kotick responded not by addressing any of the games by name, but by talking about Activision’s publishing philosophy. The games Activision Blizzard didn't pick up, he said, "don't have the potential to be exploited every year on every platform with clear sequel potential and have the potential to become $100 million franchises. … I think, generally, our strategy has been to focus… on the products that have those attributes and characteristics, the products that we know [that] if we release them today, we'll be working on them 10 years from now."

So let's say you have a great game with huge potential. Unless Kotick can release a Wii and DS port and then create a sequel every year, he just doesn't care. That sounds like a recipe for success, don't you think?

Let's pretend Bobby Kotick is a Kentucky man, and he has a stable of winning horses. You want to keep them safe, and make sure they one run the best races and stay fresh; you have to make sure people still want them to win. That's pretty sustainable, right? You'd also want to keep a look out for new up and comers, of course. But what if he raced every animal, every day? Soon they would look tired, a little beat down. Hair would fall out. Soon, instead of beautiful animals winning you huge purses every race, you have a petting zoo where children pay a quarter to feel bad for your malnourished animals.